1. Field of the Invention
The present invention is directed toward a sunglass lens having a gold appearance which under normal conditions meets the requirements of a General Purpose lens yet when encountering more extreme conditions becomes a Special Purpose lens.
2. Description of the Prior Art
Presently, sunglass lenses fall within two categories of use. The first category known as General Purpose encompasses sunglass lenses which have a light transmission characteristic of approximately 8%-40% in normal ambient temperatures. Transmittance within this range assures that all colors of the spectrum are truly rendered and the lens may be worn for General Purpose use. Examples of this type of lens are the G-15.RTM. and G-31.RTM. line of sunglass lenses available from Bausch & Lomb Incorporated of Rochester, N.Y.
Additionally, within the bounds of General Purpose lenses, are those lenses which incorporate photochromic characteristics. Glasses utilizing photochromic lenses may be worn indoors for general ophthalmic wear but have the capability of darkening from their normal state when exposed to direct sunlight. However, the degree of darkening also depends on the ambient temperature. For example, as the ambient temperature decreases, the color of the photochromic lens darkens proportionately. As mentioned previously, photochromic lenses fall within the scope described for General Purpose lenses only. Their transmittance will vary, depending on the intensity of sunlight and the ambient temperature to which the lens is being exposed. Examples of photochromic lenses are Photochromic Gray and Photochromic Brown and Ambermatic.RTM., all available from Bausch & Lomb.
A second category of sunglass lenses is known and is referred to as Special Purpose lenses. This category includes those lenses which are designed to function in more extreme conditions, such as are encountered on ski slopes where bright sunlight, intense reflection from the snow and low temperatures occur. Examples of such sunglasses utilizing Special Purpose lenses are available from Vuarnet (Nautilux and Skilynx) and Bausch & Lomb (Weatherbeater.RTM.). Lenses in this category are quite dark and, generally, have a transmittance of approximately five percent so as to provide protection for these special circumstances. Moreover, as the lenses are designed for a special purpose, they have no need to pass any color recognition tests. The lenses are so dark that recognition of the red, yellow and green colors of a traffic signal light as set forth by the American National Standards Institute, Inc. (ANSI) in their "Requirements for Nonprescription Sunglasses and Fashion Eyewear" 280.3-1977 is not possible. Accordingly, the lenses are not recommended for General Purpose wear.
The sunglass lens of the present invention provides a lens which meets the standards set forth for General Purpose use and also meets the requirements of Special Purpose lenses. Additionally, the sunglass lens of the present invention provides a lens which has an attractive gold surface color.